1. Field of the Invention
The present invention relates to an electric motor, and more particularly, it relates to an electric motor which enhances a space factor of a coil in a stator or a rotor.
2. Description of the Related Art
In general, winding and insertion of the coil in a slot of a laminated core used in an electric motor juts out from the slot to a certain extent so that wire can be easily inserted into the slot by an insertor. Consequently, a size of a part of a coil end where the coil wire exceeds a loading thickness of the core is inevitably made large and this part of the coil end not only does not contribute to an output of the electric motor but also makes an occupied area of the electric motor large, thereby creating a primary factor for decreasing the efficiency of the electric motor.
Also in an electric motor, there is a stator used in a block construction such as described in Japanese Patent Application Laid-open No. 7-67272. This is a stator configuration of a synchronous machine for making it possible to use directional electromagnetic steel plates instead of non-directional electromagnetic steel plates as used in the past, wherein a yoke and teeth comprising the stator of the electric motor are separated and the core is formed by alternately combining and connecting a divided yoke piece and a divided teeth piece toward the laminating direction after a required number of coils formed in advance by winding are temporarily assembled to fit in each location in the space of the completed stator.
In this kind of electric motor, since the yoke and the teeth comprising an electric circuit are separated from each other, a magnetic body becomes discontinuous at a dividing part and a connecting part and a magnetic resistance thereof is increased. Hence, the problem of the electric motor efficiency decreasing results. Therefore, by using the directional electromagnetic steel plate for the magnetic body of the yoke and the teeth, an increase in magnetic resistance is suppressed, but a problem is the high cost of materials due to utilization of special steel plates.